CVE-2025-50900
📋 TL;DR
This vulnerability in rebuild 4.0.4 allows unauthenticated attackers to bypass authentication by manipulating URL paths. Attackers can access sensitive information or escalate privileges by exploiting improper access control in the web interceptor. All systems running the affected version are vulnerable.
💻 Affected Systems
- getrebuild/rebuild
📦 What is this software?
Rebuild by Getrebuild
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with administrative privileges, data exfiltration, and potential lateral movement within the network.
Likely Case
Unauthorized access to sensitive data, privilege escalation to administrative functions, and potential data manipulation.
If Mitigated
Limited impact with proper network segmentation and additional authentication layers, though core vulnerability remains.
🎯 Exploit Status
The vulnerability is straightforward to exploit with basic HTTP manipulation skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
1. Monitor the rebuild GitHub repository for security updates
2. Apply any available patches immediately
3. Restart the rebuild service after patching
🔧 Temporary Workarounds
Web Application Firewall Rule
allBlock requests containing URL-encoded path manipulation attempts targeting /error endpoints
Network Segmentation
allRestrict access to rebuild instances to authorized users only
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure
- Deploy additional authentication layers before the rebuild application
🔍 How to Verify
Check if Vulnerable:
Check if running rebuild version 4.0.4 by examining application version or deployment configurationCheck Version:
Check application configuration files or deployment manifests for version informationVerify Fix Applied:
Verify version is updated beyond 4.0.4 and test authentication bypass attempts fail📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful access
- Unusual URL patterns with encoded characters
- Access to /error endpoints from unauthenticated sources
Network Indicators:
- HTTP requests with URL-encoded paths targeting authentication bypass
- Unusual traffic patterns to administrative endpoints
SIEM Query:
source="rebuild" AND (uri="*%2Ferror*" OR uri="*/error*") AND auth_status="failed"